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Peacock on Prime, now idle too high and Air filter full of fuel

Discussion in 'The Garage' started by tim996, Jun 9, 2015.

  1. tim996

    tim996 XS400 New Member

    Hi guys!

    First, I wanna say that I love this forum. I have my first bike and you guys helped me a lot through all the threads.

    Aright I have a XS400 RL 84 (Seca). It works well and I'm turning it in something nice!

    I empty all the old oil, put new in, did 100 km, changed the filter and the oil again. Changed all the flashers for LEDs, put new headlights, changed the front bearings, both tires. Check the brakes. Plasti-dip the hole thing...

    It runs well, no issue of carbs (didn't check them yet) the throttle response, idle and everything was fine.

    So here's my problem :

    I wanted to check my air filter but when I did, it was full of fuel... And my oil smells gas...

    The thing is that I had the peacock on PRI (Prime) - I thought it stood for "Primary" but whatever... I know now - thanks to all of you - the difference. So I let the air filter dried overnight and put the peacock in ON position.

    The bike seemed to run fine but after a couple of minutes the RPM started going up at red lights. (2000-2500rpm). So I unscrewed a little bit the idle screw and it went down. But it still 80% of the time goes at 2000 rpm and doesn't go down...

    I plan to change the air filter, oil and oil filter but I've read that some of you guys were talking about the floats in the carbs... Did I screw up the carbs? What would you do?

    Thanks a lot!!
    Tim
     
  2. ryu77us

    ryu77us XS400 Member

    Hey Tim welcome,

    Sounds like the needle in the float for the carb is not seating properly. In the PRI position fuel is able to free flow to fill the bowl for prime, in the ON position it uses suction in the intake manifold(boot) to pull on a diaphragm inside the fuel selector valve. If let on prime and the needle did not seat in the float bowl it will continue to fill up thru the jet and into the carb, and can run into the cylinder and or the air filter box as you had.

    If fuel is leaking into the carb excessively while running the bike can start to idle high like when the choke is on. The best would be to check the float shut off height, it can be down by attaching clear surgical tube to the bottom fitting on the carb bowl, with it held next to the carb and the carb full of fuel you should be able to see the "water line" of where the fuel level is at. The manual has an excerpt that tells you allowable height and the tang inside the carb can be adjusted to compensate for that. It may also be something stuck under the seat of the needle valve as well.

    I would say that your carbs are fine but you may want to blow them out to make sure no fuel is in any additional air metering passages that may be in the carb.

    I hope this helps
     
  3. sproutroot

    sproutroot XS400 Member

    When trying to get a needle valve to seat, the first thing I always do is to firmly tap each fuel bowl with a rubber mallet. It works a lot more often than you'd think.
     
  4. tim996

    tim996 XS400 New Member

    Aright, I'll look into it!!

    Thanks a lot guys!
     
  5. bobbinyamaha

    bobbinyamaha XS400 Member

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    NewYork
    Quick question. I recently picked up a 1980 xs400 G. Cleaned tank and carbs. Treated with sea foam. Synced carbs. For a week the bike ran great. Now the bike had been gettin starved for gas and will only stay running when pepcock on pri setting? This valve has res.on.pri and has one fuel line that goes to the leftside float bowl. Any suggestions where to start?
     
  6. xschris

    xschris a lifestyle not a trend Top Contributor

    Make sure the vacuum line is hooked up. If it is the petcock may need to be cleaned/rebuilt.
     
  7. bobbinyamaha

    bobbinyamaha XS400 Member

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    NewYork
    I may have over looked it, but I didn't see where any vacuum line would go to the petcock ? I did notice also when I pulled the tank. When petcock was on position it leaked freely.
     
  8. xschris

    xschris a lifestyle not a trend Top Contributor

    Take a pic of what you have. The stock petcock should only flow gas freely when set to prime. In the on and reserve position gas should flow only with the motor running as it is vacuum operated. A hose connects to the back of the petcock and then attaches to the right side intake boot air barb.
     
  9. bobbinyamaha

    bobbinyamaha XS400 Member

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    Running good again. Vacuum line connects to the top of.my petcock. It was d/c. Running good again. On pos

    Thank u

    Having frontend alighnment issues now. My front tire is misaligned with my bars. I tried the loosining everything and pushin down on it. Still no results
     

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